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Developing hole-transport materials (HTMs) with high hole mobility is critical for constructing efficient perovskite solar cells (PSCs). We present a design strategy for improving hole mobility and PSC performance using a stable zinc complex-based HTM BPZ23. Compared to its non-metal counterpart (BP21), the BPZ23 demonstrated a 59.42% increase in hole mobility, resulting in a good perovskite layer with reduced trap-assisted recombination. As a result, the power conversion efficiency of the fabricated inverted PSC using BPZ23 is up to 19.75%, which is one of the highest reported for any transition metal complex-based HTM employed in inverted PSC. This research demonstrates a simple and efficient method for increasing hole mobility in HTMs and improving the photovoltaic performance of PSCs. [ABSTRACT FROM AUTHOR]

Hole mobility is critical to the power conversion efficiencies of perovskite solar cells (PSCs). Organic small‐molecule hole‐transporting materials (HTMs) have attracted considerable interest in PSCs due to their structural flexibility and operational durability, but they suffer from modest hole mobility. On the other hand, inorganic HTMs with good hole mobility are inflexible in structural variation and exhibit unsatisfactory cell efficiency. In this study, a ligand BT28 and its zinc‐based coordination complex BTZ30 were synthesized, characterized, and investigated as HTMs for PSC applications. The mixed‐halide perovskites can be grown uniformly with large crystalline grains on both HTMs, which exhibit similar optical and electrochemical properties. However, it was discovered that the BTZ30‐based solar cell exhibited an open‐circuit voltage of 1.0817 V and a high short‐circuit current density of 23.1392 mA cm−2 with a champion power conversion efficiency of close to 20 %. The performance difference between the two HTMs can be attributed to the difference in their hole mobilities, which is 63.31 % higher for BTZ30 than BT28. The comparison of non‐metal and metal HTMs revealed the importance of considering hybrid structures to overcome some shortcomings associated with organic and inorganic HTMs and achieve high‐performance PSCs. [ABSTRACT FROM AUTHOR]

Water splitting is promising, especially for energy and environmental applications; however, there are limited studies on the link between water splitting and cancer treatment. Upconversion nanoparticles (UCNPs) can be used to convert near-infrared (NIR) light to ultraviolet (UV) or visible (Vis) light and have great potential for biomedical applications because of their profound penetration ability, theranostic approaches, low self-fluorescence background, reduced damage to biological tissue, and low toxicity. UCNPs with photocatalytic materials can enhance the photocatalytic activities that generate a shorter wavelength to increase the tissue penetration depth in the biological microenvironment under NIR light irradiation. Moreover, UCNPs with a photosensitizer can absorb NIR light and convert it into UV/vis light and emit upconverted photons, which excite the photoinitiator to create H2, O2, and/or OH˙ via water splitting processes when exposed to NIR irradiation. Therefore, combining UCNPs with intensified photocatalytic and photoinitiator materials may be a promising therapeutic approach for cancer treatment. This review provides a novel strategy for explaining the principles and mechanisms of UCNPs and NIR-driven UCNPs with photocatalytic materials through water splitting to achieve therapeutic outcomes for clinical applications. Moreover, the challenges and future perspectives of UCNP-based photocatalytic materials for water splitting for cancer treatment are discussed in this review. [ABSTRACT FROM AUTHOR]

The hole‐transporting material (HTM) in perovskite solar cells (PSCs) provides an ideal interface with the perovskite layer for hole collection while influencing the perovskite crystalline structure and morphology. This article presents SIM and DIM, two new dopant‐free imidazolium‐based HTMs with charged units accompanied by counter ions that show the potential to function as ionic HTMs and ionic liquid additives and help improve the efficiency and stability of inverted PSCs. DIM‐based PSCs demonstrates exceptional performance with a high‐power conversion efficiency of 19.15%, attributed to improved passivation of perovskite interface defects. Furthermore, these new imidazolium salt‐based HTMs can be manufactured economically, making them a viable option for mass production and PSC commercialization. [ABSTRACT FROM AUTHOR]

In the operating mechanisms of perovskite solar cells, hole-transporting materials (HTMs) facilitate directional charge transfer and electron blocking. In addition, HTMs are also important in forming the perovskite layers for inverted perovskite solar cells, improving device efficiency. We present a method for increasing efficiency by ionizing HTMs, introducing defect-passivating abilities, improved interfacial properties, and ideal surface topographies. Compared to their non-ionized counterpart, the ionic HTMs have well-matched energy levels and smooth perovskite layers, resulting in higher short-circuit current densities. These experimental findings are corroborated by atomistic first principle electronic structure calculations of model perovskite systems. Furthermore, we conducted a comparative study of different ionizing counter anions for HTMs. The iodide-based ionic HTM, PMO-I, has a maximum efficiency of 20.46%, 1.71% higher than that of the non-ionic HTM, PMO (18.75%). [ABSTRACT FROM AUTHOR]

Small-molecule hole-transporting materials (HTMs) have gained much attention due to their structural flexibility, material properties, and stabilities, allowing for enhanced operational durability in perovskite photovoltaics. We synthesized and investigated a new class of donor–acceptor–donor (D–A–D) configured ligand type hetero-structured small molecule, WWC106, serving as the HTM to enable high-efficiency mixed-halide lead perovskite solar cells. WWC106 is a benzimidazole-centered dopant-free HTM composed of three donors: two 4-methoxy-N-(4-methoxyphenyl)-N-phenylanilines (TPAs) and one 2-(2,2-bis(4-methoxyphenyl)vinyl)-5-methylthiophene. One of the two TPA donors is linked to the benzimidazole via a pyridine unit. Scanning electron microscopy, photoluminescence (PL) time-resolved PL, and space charge limited current measurements on WWC106 HTMs show perovskite formation with good morphology, efficient hole extraction, and hole mobility. The new D–A–D configured WWC106-based device exhibited a high open-circuit voltage of 1.09 V and a high short circuit current density of 20.76 mA cm−2, with the highest power conversion efficiency of 17.75%. [ABSTRACT FROM AUTHOR]

Due to the excellent thermal property of Na superionic conductors (NASICON), research has focused on studying crystal structure parameters under high temperature conditions. In this study, different ratios of anion groups were regulated to induce vacancy defects on the Eu-doped phosphate phosphor Na2.87Sc2(PO4)y:0.13Eu2+, y = 2.6–3.0. When the amount of the anion group increased, a structural transformation was induced from γ to β-phase. Using the X-ray absorption near edge structure (XANES) technique, this phenomenon was found to be caused by Eu3+ and Eu2+ coexisting due to the amount of anion group. It is rare to observe this situation with 2D X-ray fluorescence (XRF) technology, with direct evidence of the shielding effect provided by XRF mapping. We speculate that the oxidation reaction creates trivalent europium due to the lack of the –PO4 anion group to protect the divalent europium (Eu2+) and we explain the luminescence mechanism by a charge compensation model. Thermal stability was maintained at 90% from room temperature to 150 °C. The pathway of the reduction mechanism and the location of the ground level from Eu2+ (β-phase) to Eu3+ (γ-phase) are evidenced by high-pressure spectroscopy. Finally, this study proposes a generic path for the anion group phosphor research. [ABSTRACT FROM AUTHOR]

Interfaces play a decisive role in perovskite solar cells' power conversion efficiency and their long‐term durability. Small‐molecule hole‐transporting materials (HTMs) have grabbed enormous attention due to their structural flexibility, material properties, and stabilities, allowing for improved operational durability in perovskite photovoltaics. This study synthesizes and investigates a new class of benzimidazole‐based small molecules, named YJS001 and YJS003, serving as the HTMs to enable high‐efficiency mixed‐cation mixed‐halide perovskite solar cells. The benzimidazole‐based materials are dopant‐free HTMs composed of donor and acceptor building blocks that are designed to engineer the energy level alignment near the HTM/perovskite interface. Mixed‐cation mixed‐halide perovskites can be grown uniformly on both HTMs with large crystalline grains. It is discovered that the donor‐rich YJS003‐based solar cell exhibits a high open‐circuit voltage of 1.09 V with a champion power conversion efficiency of over 20%. Power‐dependent current–voltage characteristics of the solar cells are analyzed, from which the high performance of YJS003's excellent hole mobility and well‐aligned energy level is attributed. This work introduces a new class of benzimidazole‐based small molecules as HTMs, that paves the path for dopant free interface material development for commercialization of perovskite solar cells. [ABSTRACT FROM AUTHOR]

New isomeric sensitizers containing an imine–carbene (IC)-based ancillary ligand, isomers IC101 and IC102, were designed for application in dye-sensitized solar cells (DSSCs). These ruthenium complexes were synthesized and isolated using simple purification methods. The DSSCs sensitized with IC101 and IC102 exhibited overall conversion efficiencies of 6.32% and 6.59%, respectively. Although these two isomers gave similar device output, reduction in the power conversion efficiency (5.52%) was observed when the cell was fabricated using a 1 : 1 mixture of both sensitizers. The results highlight the importance of isomeric purity of the sensitizing complexes to gain high performance DSSCs. [ABSTRACT FROM AUTHOR]

Two dipolar molecules based on a thieno-imidazole core, AI109 and AI112, were developed to study the effect of imparting polarity on the hole transport properties in inverted perovskite solar cells (PSCs). These hole transport materials (HTMs) exhibit comparable optoelectronic properties but distinct film morphology and charge transport characteristics. Besides, the new materials with very low concentrations (1 mg mL−1) are able to form smooth and continuous films. The PSCs based on AI109 and AI112 without any dopants and additional interlayers have achieved increased power conversion efficiencies of 13.32% and 13.42%, respectively, compared to those of the standard HTMs, 2,2′,7,7′-tetrakis(N,N′-di-p-methoxyphenylamino)-9,9′-spirobifluorene [Spiro-OMeTAD, (11.62%)] and poly(3,4-ethylenedioxythiophene) polystyrene sulfonate [PEDOT:PSS, (12.01%)]. The excellent hole mobility and the superior film morphology of the AI-HTMs account for their higher efficiencies. [ABSTRACT FROM AUTHOR]

Perovskite quantum dots (QDs), such as all-inorganic CsPbX3 (X = Cl, Br, and I), are novel fluorescent semiconductor nanocrystals (NCs) that have attracted tremendous attention due to their excellent optical properties and great applications (e.g. display backlights, light-emitting diodes, and photodetectors). The instability and toxicity of lead-based perovskite QDs, however, are intrinsic defects that obstruct their application and commercialization. Poison is released from the lead of the unstable CsPbX3 NCs, which are generally ascribed to the labile surface, ionic character, and metastable structure. In this work, lead-free Cs2SnCl6 perovskite NCs are successfully synthesized via hot injection. Particularly, by controlling the different precursor ratios, phase transition (CsCl to Cs2SnCl6) was clearly observed from X-ray diffraction (XRD) measurements. The Cs2SnCl6 NCs exhibited a highly efficient deep-blue emission at 425 nm, with a 55 nm Stokes shift and an 84 nm full width at half maximum (FWHM). After doping Mn ions, the preferred formation of CsSnCl3:Mn2+ with double-wavelength emission was demonstrated based on the XRD and photoluminescence spectra. The study showed that doping synthesis should be widely used in lead-free perovskite NCs as an important strategy for next-generation solid-state lighting. [ABSTRACT FROM AUTHOR]

Ruthenium metal complexes consisting of various functionalized carbene-pyridyl anchoring ligands were synthesized, characterized, and tested for their power conversion capabilities. Carboxylate (DC101), hydroxamate (DC107), and acyl azide (DC108) groups were explored as anchors to identify a suitable and efficient binding functionality for the unique characteristic carbene-pyridyl ligand. The hydroxamate anchoring group was shown to be the most efficient anchoring group for the carbene-pyridyl ligand and the device based on dye DC107 exhibited the best efficiency (η) of 4.97% compared to those of the other prepared sensitizers. Electrochemical impedance spectroscopy studies on the devices based on these dyes justified their performances. This is the first case of an investigation utilizing σ electron donating carbene-pyridine as the anchoring ligand and it was found to be more suitable for use as an ancillary group. [ABSTRACT FROM AUTHOR]

New heteroleptic Ru(ii) complexes consisting of pyridylimine as an ancillary ligand were synthesized and characterized for applications in dye sensitized solar cells. Complexes with cis and trans configurations around the central ruthenium metal were obtained using simple synthetic protocols by varying the substituents on the pyridylimine ligands. The geometries of these complexes were confirmed by single crystal X-ray analysis. The effect of the difference in the configurations of these complexes on their device performances was studied and the sensitizer with a trans arrangement around the metal showed a higher overall conversion efficiency (η) of 7.27% than that of the cis configured complex (η = 2.04%). [ABSTRACT FROM AUTHOR]

A sensitive and selective hydrazine sensor was developed by β-cyclodextrin modified palladium nanoparticles decorated reduced graphene oxide (PdNPs-β-CD/rGO) nanocomposite. The PdNPs-β-CD/rGO hybrid material was prepared by simple electrochemical method. The hydrophobic cavity of β-CD ineracts with palladium nanoparticles by hydrophobic interaction and further it is uniformly assembled on the rGO surface through hydrogen bond formation, which is clearly confirmed by FT-IR, FESEM and TEM. The high electrocatalytic activity of hydrazine oxidation was observed at −0.05 V (vs. Ag/AgCl) on PdNPs-β-CD/rGO modified electrode; due to the excellent stabilization, high catalytic activity and large surface area of the PdNPs-β-CD/rGO composite. The PdNPs-β-CD/rGO fabricated hydrazine sensor exhibited an excellent analytical performance, including high sensitivity (1.95 μA μM−1 cm−2), lower detection limit (28 nM) and a wide linear range (0.05 to 1600 μM). We also demonstrated that the PdNPs-β-CD/rGO nanocomposite modified electrode is a highly selective and sensitive sensor towards detection of hydrazine among the various interfering species. Hence, the proposed hydrazine sensor is able to determine hydrazine in different water samples. [ABSTRACT FROM AUTHOR]

A series of yellow-emitting La0.975−xGdxSr2AlO5:0.025Ce3+ phosphors have been synthesized by a solid-state reaction. All the samples retain the same tetragonal crystal structure, and the phosphors emit yellow emission with a peak maximum shifting from 540 nm to 556 nm, depending on the Gd/La ratio, when excited by 440 nm blue light. Their temperature dependent photoluminescence, fluorescence decay curves, and CIE values were also discussed. With increasing Gd/La ratio, the red-shift behaviors can be ascribed to the enhancing covalence, and the emission intensities first increased, then decreased, and finally increased to the maximum at x = 0.6. A white light-emitting diode (w-LED) lamp was fabricated based on the selected yellow-emitting La0.375Gd0.6Sr2AlO5:0.025Ce3+ phosphors combined with a 460 nm blue-emitting InGaN chip. The packaged w-LED lamp gave CIE chromaticity coordinates of (0.3562, 0.3660) with a warm color temperature of 4664 K and a color rendering index of 83. [ABSTRACT FROM AUTHOR]

The application of freestanding TiO nanotubes on the photovoltaic performance of dye-sensitized solar cells utilizing front side illumination has been investigated. TiO nanotubes were grown on Ti foil using the anodization process at a constant voltage of 60 V for various anodization times such as 2, 4, and 6 h. Subsequently, the formations of freestanding films of close-ended and open-ended TiO nanotubes were carried out via a second anodization step at 40 and 80 V, respectively. X-ray diffraction analysis revealed the formation of amorphous structure TiO nanotubes before annealing and anatase phase after annealing at 450 °C. The diameter (60-90-nm-inner diameter) and thickness (7-19 μm) of TiO nanotubes were measured from scanning electron microscopy and transmission electron microscopy analysis. The detached TiO nanotube films were affixed on FTO substrates employing anatase TiO paste. The fixation of freestanding TiO nanotubes on FTO substrates can be categorized as three parts namely: close-ended nanotubes downside, close-ended nanotubes upside, and open-ended nanotubes. Among the various anodization times, the cells fabricated using 6 h anodized TiO nanotubes photoelectrode attained excellent photoelectric efficiencies of 6.91, 6.47, and 7.69 % for close-ended downside, close-ended upside and open ended, respectively. The DSSCs based on open-ended photoelectrodes achieved the highest photoelectrical conversion efficiency are due to higher dye loading amount. [ABSTRACT FROM AUTHOR]

A new type of carbene-based ruthenium sensitizer, CB104, with a highly conjugated ancillary ligand, diphenylvinylthiophene-substituted benzimidazolepyridine, was designed and developed for dye-sensitized solar cell applications. The influence of the thiophene antenna on the performance of the cell anchored with CB104 was investigated. Compared with the dye CBTR, the conjugated thiophene in the ancillary ligand of CB104 enhanced the molar extinction coefficient of the intraligand π-π* transition and the intensity of the lower energy metal-to-ligand charge-transfer band. However, the incident photon-to-current conversion efficiency spectrum of the cell anchored with CB104 (0.15 m M) showed a maximum of 63 % at 420 nm. The cell sensitized with the dye CB104 attained a power conversion efficiency of 7.30 %, which was lower than that of the cell with nonconjugated sensitizer CBTR (8.92 %) under the same fabrication conditions. The variation in the performance of these two dyes demonstrated that elongating the conjugated light-harvesting antenna resulted in the reduction of short-circuit photocurrent density, which might have been due to the aggregation of dye molecules. In the presence of a coabsorbate, chenodeoxycholic acid, the CB104-sensitized cell exhibited an enhanced photocurrent density and achieved a photovoltaic efficiency of 8.36 %. [ABSTRACT FROM AUTHOR]

The incorporation of electron-withdrawing groups in carbene based ruthenium complexes significantly affected their light-harvesting capabilities. The remarkable increase in the conversion efficiency was exhibited by the primary amide substituted sensitizer, CI103 (9.32%), compared to that of CI101 (5.44%) and the N719 dye (8.43%). The finding gives an efficient approach to enhance the photocurrent density and the power conversion efficiency of the solar cell. [ABSTRACT FROM AUTHOR]

The microstructure design of TiO nanoparticles for photoanodes is an important issue in optimization of dye-sensitized solar cell (DSSC) performance. Up to date, the nanostructured TiO particles have been extensively employed as active layers. However, less attention has been focused on the development of various TiO nanostructures as the light-scattering layers (LSLs). In the present work, a facile hydrothermal method was utilized to prepare quasi-cube TiO (qcTiO) nanoparticles as the LSL for the DSSC photoanode. The anatase qcTiO nanoparticles had a size distribution of 30-60 nm. The photoconversion efficiency of the cell with the qcTiO LSL was enhanced 12 %, compared to the TiO film without a scattering layer. The above enhancement was further vindicated by the incident photon-to-current efficiency measurement. The effect of the qcTiO LSL on electron transport and charge recombination of the DSSC was studied by electrochemical impedance spectroscopy. The experiment results revealed that the enhanced photovoltaic performance is attributed to the better light-harvesting capacity, longer electron life time, and less charge recombination of the qcTiO nanoparticles. [ABSTRACT FROM AUTHOR]

A new series of N-heterocyclic carbene (NHC)-pyridine ruthenium complexes incorporating a carbene unit as an ancillary ligand were designed and successfully synthesized by using simple synthetic methods. The photophysical, electrochemical and photovoltaic properties of these NHC-pyridine based ruthenium complexes were investigated. These complexes showed photoelectric conversion efficiencies in the range of 6.43 ∼ 7.24% under the illumination of AM 1.5 (100 mW cm−2). Interestingly, the modifications on the ancillary ligand of these sensitizers by removal of an alkoxyl group and replacement of the octyl chain with a 3,5-difluorobenzyl group showed a 13% increase in the conversion efficiency for the CifPR dye. These results demonstrated that structural modifications on the NHC-pyridine ancillary ligand of ruthenium complexes results in dye-sensitized solar cells exhibiting a comparable cell performance to that obtained using the standard N719 dye. [ABSTRACT FROM AUTHOR]

The research achievements of a university chemistry lab regarding dye-sensitized solar cells (DSSCs) were transformed into a high school hands-on course by simplifying the experimental steps and equipment. Our research methodology was action research. We verified the DSSC course step by step. First, 10 members of a high school science study club helped to revise the course over a school semester. A questionnaire survey revealed that all students agreed that the course increased their understanding of DSSCs and solar cells. Second, 35 students were enrolled in a 10th-grade elective energy course to study the revised DSSC topics for 3 weeks. A five-point Likert scale was used to collect students' feedback, and students reported looking forward to making their own high-performance DSSC modules (4.60) and stated that being able to make their own solar cell was a great accomplishment (4.49). Third, the course was implemented at a junior high school science camp, and the 37 participating students were all able to complete the hands-on experiment. In the questionnaire survey, the students expressed that they enjoyed learning about scientific principles through a hands-on approach (4.59). Fourth, most of the 12 schoolteachers who voluntarily participated in the DSSC workshop agreed that integrating DSSC activity into school courses would be conducive to multidisciplinary learning. This course could facilitate participants' self-evaluations in science knowledge, experimental skills, learning motivations, and positive attitudes toward sustainability. [ABSTRACT FROM AUTHOR]

The funnel glass of the CRT monitor contains about 22–28% of lead oxide, of which lead is a highly toxic species and hazardous to the environment. This study proposes a process to form a protective layer of SiO2 film coating on the funnel glass to reduce the hazardous effect of lead leaching to the environment. The film coating benefits from the advantages of the sol–gel method. There are two key procedures of the stabilization technique, including the alkaline treatment and the formation of SiO2 coating from TEOS. The results show that the funnel glass powder treated with 10 M NaOH can produce a mushy layer on the surface. The mushy layer, which comprises OH− and water, can promote the formation of the SiO2 film layer on the surface of funnel glass powder. The conditions of the SiO2 film coating proposed in this study are: alkaline treatment by 10 M NaOH, the addition ratio of TEOS and funnel glass powder 2: 1, reaction temperature 40 °C, and reaction time 1.3 h. The EDS and ESCA results show that the Pb peak intensity on the surface of funnel glass decreases with the film coating. In the TCLP test, the leaching amount for Pb of the SiO2 film coated funnel glass powders is 0.7 mg/L, which is far lower than the standard in Taiwan EPA. Based on the experimental results, the formation mechanism of the SiO2 film layer on the surface of waste funnel glass powder is proposed. This study demonstrates that the SiO2 film coating is a potentially effective method to solve the problem of the waste funnel glass. [ABSTRACT FROM AUTHOR]

New D-π-A configured organic sensitizers featuring halogen-substituted oxindole-bridged acceptor units have been synthesized for dye-sensitized solar cells applications. Among fluorine, bromine, and iodine substitution, the cell based on bromine incorporated dye exhibited the highest efficiency. The oxindoles in these sensitizers were found to assist the electron injection through the chelation of their amide carbonyl groups to the TiO2 surface. This study provides an alternate approach for future rational dye design to gain excellent DSSC performance. [ABSTRACT FROM AUTHOR]

A molecular beam study of the Cl2+GaAs(s) reaction has been performed for surface temperatures in the range of 300–550 K. The gas phase neutral reaction products are identified by mass spectroscopy using electron bombardment ionization. Detailed analysis of the surface temperature dependence of the mass spectrum of the observed reaction products indicates that only three neutral reaction products are formed in this temperature range: GaCl3, AsCl3, and As4. At low (high) surface temperatures, only AsCl3 (As4) is observed. The ratio of the etching rates of Ga and As is independent of the surface temperature and within the range expected for stoichiometric etching. The change in the mode of As removal with surface temperature for the incident Cl2 flux implies that surface diffusion is important at surface temperatures above 400 K. [ABSTRACT FROM AUTHOR]